doc: add app engine docs to the readme
Change-Id: I71dc6930470ad64659a419dd578c91bb14c7cab2
Reviewed-on: https://go-review.googlesource.com/7713
Reviewed-by: David Symonds <dsymonds@golang.org>
diff --git a/README.md b/README.md
index ecf9c4e..a5afeca 100644
--- a/README.md
+++ b/README.md
@@ -16,3 +16,49 @@
* [godoc.org/golang.org/x/oauth2/google](http://godoc.org/golang.org/x/oauth2/google)
+## App Engine
+
+In change 96e89be (March 2015) we removed the `oauth2.Context2` type in favor
+of the [`context.Context`](https://golang.org/x/net/context#Context) type from
+the `golang.org/x/net/context` package
+
+This means its no longer possible to use the "Classic App Engine"
+`appengine.Context` type with the `oauth2` package. (You're using
+Classic App Engine if you import the package `"appengine"`.)
+
+To work around this, you may use the new `"google.golang.org/appengine"`
+package. This package has almost the same API as the `"appengine"` package,
+but it can be fetched with `go get` and used on "Managed VMs" and well as
+Classic App Engine.
+
+See the [new `appengine` package's readme](https://github.com/golang/appengine#updating-a-go-app-engine-app)
+for information on updating your app.
+
+If you don't want to update your entire app to use the new App Engine packages,
+you may use both sets of packages in parallel, using only the new packages
+with the `oauth2` package.
+
+ import (
+ "golang.org/x/net/context"
+ "golang.org/x/oauth2"
+ "golang.org/x/oauth2/google"
+ newappengine "google.golang.org/appengine"
+ newurlftech "google.golang.org/urlfetch"
+
+ "appengine"
+ )
+
+ func handler(w http.ResponseWriter, r *http.Request) {
+ var c appengine.Context = appengine.NewContext(r)
+ c.Infof("Logging a message with the old package")
+
+ var ctx context.Context = newappengine.NewContext(r)
+ client := &http.Client{
+ Transport: &oauth2.Transport{
+ Source: google.AppEngineTokenSource(ctx, "scope"),
+ Base: &newurlfetch.Transport{Context: ctx},
+ },
+ }
+ client.Get("...")
+ }
+
